SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fb2610d95de6a28f771b91450811bc674d08cb07fbb92b0e31e6d59652109c0a' 
  AND token = 'J93/vnQw6GTjYKbFSVn4+5gvVvkil3Z1ZuyheKXgt+I=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}